/*
 * Copyright 2010 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package de.google.android.apps.iosched.io;

import static de.google.android.apps.iosched.util.ParserUtils.sanitizeId;
import static de.google.android.apps.iosched.util.ParserUtils.AtomTags.ENTRY;
import static org.xmlpull.v1.XmlPullParser.END_DOCUMENT;
import static org.xmlpull.v1.XmlPullParser.START_TAG;

import de.google.android.apps.iosched.provider.ScheduleContract;
import de.google.android.apps.iosched.provider.ScheduleContract.SyncColumns;
import de.google.android.apps.iosched.provider.ScheduleContract.Vendors;
import de.google.android.apps.iosched.util.Lists;
import de.google.android.apps.iosched.util.ParserUtils;
import de.google.android.apps.iosched.util.SpreadsheetEntry;

import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;

import android.content.ContentProviderOperation;
import android.content.ContentResolver;
import android.content.ContentValues;
import android.database.Cursor;
import android.net.Uri;
import android.util.Log;

import java.io.IOException;
import java.util.ArrayList;

/**
 * Handle a remote {@link XmlPullParser} that defines a set of {@link Vendors}
 * entries. Assumes that the remote source is a Google Spreadsheet.
 */
public class RemoteVendorsHandler extends XmlHandler
{
	private static final String TAG = "VendorsHandler";
	/** Base {@link Uri} where {@link Columns#COMPANY_LOGO} images live. */
	private static final Uri LOGO_BASE = Uri.parse("http://www.java-forum-stuttgart.de/vortragsprogramm.html");

	public RemoteVendorsHandler()
	{
		super(ScheduleContract.CONTENT_AUTHORITY);
	}

	@Override
	public ArrayList<ContentProviderOperation> parse(XmlPullParser parser, ContentResolver resolver)
			throws XmlPullParserException, IOException
	{
		final ArrayList<ContentProviderOperation> batch = Lists.newArrayList();

		// Walk document, parsing any incoming entries
		int type;
		
		while ((type = parser.next()) != END_DOCUMENT)
		{
			if (type == START_TAG && ENTRY.equals(parser.getName()))
			{
				// Process single spreadsheet row at a time
				final SpreadsheetEntry entry = SpreadsheetEntry.fromParser(parser);
				final String vendorId = sanitizeId(entry.get(Columns.COMPANY_NAME));
				final Uri vendorUri = Vendors.buildVendorUri(vendorId);
				// Check for existing details, only update when changed
				final ContentValues values = queryVendorDetails(vendorUri, resolver);
				final long localUpdated = values.getAsLong(SyncColumns.UPDATED);
				final long serverUpdated = entry.getUpdated();
				
				if (Log.isLoggable(TAG, Log.VERBOSE))
				{
					Log.v(TAG, "found vendor " + entry.toString());
					Log.v(TAG, "found localUpdated=" + localUpdated + ", server=" + serverUpdated);
				}
				
				if (localUpdated >= serverUpdated)
					continue;

				// Clear any existing values for this vendor, treating the
				// incoming details as authoritative.
				batch.add(ContentProviderOperation.newDelete(vendorUri).build());

				final ContentProviderOperation.Builder builder = ContentProviderOperation
						.newInsert(Vendors.CONTENT_URI);

				builder.withValue(SyncColumns.UPDATED, serverUpdated);
				builder.withValue(Vendors.VENDOR_ID, vendorId);
				builder.withValue(Vendors.NAME, entry.get(Columns.COMPANY_NAME));
				builder.withValue(Vendors.LOCATION, entry.get(Columns.COMPANY_LOCATION));
				builder.withValue(Vendors.DESC, entry.get(Columns.COMPANY_DESC));
				builder.withValue(Vendors.URL, entry.get(Columns.COMPANY_URL));
				builder.withValue(Vendors.PRODUCT_DESC, entry.get(Columns.PRODUCT_DESC));

				// Inherit starred value from previous row
				if (values.containsKey(Vendors.STARRED))
				{
					builder.withValue(Vendors.STARRED, values.getAsInteger(Vendors.STARRED));
				}

				// Assign track
				final String trackId = ParserUtils.translateTrackIdAlias(sanitizeId(entry.get(Columns.COMPANY_POD)));
				
				builder.withValue(Vendors.TRACK_ID, trackId);

				// Assign logo path
				final String logoUrl = LOGO_BASE.buildUpon().appendPath(entry.get(Columns.COMPANY_LOGO)).build()
						.toString();
				
				builder.withValue(Vendors.LOGO_URL, logoUrl);		
				// Normal vendor details ready, write to provider
				batch.add(builder.build());
			}
		}
		return batch;
	}

	private static ContentValues queryVendorDetails(Uri uri, ContentResolver resolver)
	{
		final ContentValues values = new ContentValues();
		final Cursor cursor = resolver.query(uri, VendorsQuery.PROJECTION, null, null, null);
		
		try
		{
			if (cursor.moveToFirst())
			{
				values.put(SyncColumns.UPDATED, cursor.getLong(VendorsQuery.UPDATED));
				values.put(Vendors.STARRED, cursor.getInt(VendorsQuery.STARRED));
			}
			else
			{
				values.put(SyncColumns.UPDATED, ScheduleContract.UPDATED_NEVER);
			}
		}
		finally
		{
			cursor.close();
		}
		return values;
	}

	private interface VendorsQuery
	{
		String[] PROJECTION =
		{ SyncColumns.UPDATED, Vendors.STARRED, };

		int UPDATED = 0;
		int STARRED = 1;
	}

	/** Columns coming from remote spreadsheet. */
	private interface Columns
	{
		String COMPANY_NAME = "companyname";
		String COMPANY_LOCATION = "companylocation";
		String COMPANY_DESC = "companydesc";
		String COMPANY_URL = "companyurl";
		String PRODUCT_DESC = "productdesc";
		String COMPANY_LOGO = "companylogo";
		String COMPANY_POD = "companypod";
		@SuppressWarnings("unused")
		String COMPANY_TAGS = "companytags";
	}
}
